Intelligent 5-Axis machining of fabrications
01 May 2008
JCB Loadall installs one of UK's largest machining centres,
with 16-metre X-axis. The trouble with CNC machining of welded fabrications is that every one is slightly different, making it difficult to align the component prior to starting the milling and drilling program. To solve this problem, the UK 's leading construction and agricultural equipment manufacturer, JCB, has installed a twin-spindle, 5-axis machining centre with pre-cycle probing to assist in the manufacture of steel booms for its Loadall telescopic handler range.
Manufactured in Germany by SHW and supplied through UK agent, Geo Kingsbury Machine Tools, the machining centre started operating 24/7 at JCB's Loadall's manufacturing facility in Rocester in 2007, where it has improved quality, efficiency and reliability.
With a working envelope of X:16m x Y:1.6m x Z:1.3m, the SHW Powerspeed 5 Duplex is essentially two travelling-column, 5-axis machining centres installed on either side of a fixed, ground-level table. The configuration allows a boom to be machined in one hit on both sides simultaneously, without having to rotate or reposition the component.
The long X-axis of the table gives sufficient space for a boom to be machined at one end while another is being clamped at the other end. The fixtures, which are automatically actuated from the machine control, are designed to accept inner and outer sections of six variants of boom, all of which are between six and seven metres long.
Before a cutting cycle can start, the control awaits the results of an automatic probing cycle that determines the exact position of the fabricated component and of welded bosses along its length. The control then calculates the best fit with a 3D CAD model of the relevant boom, and applies offsets in X, Y and Z to ensure the most accurate machining possible.